Division of Nephrology and University Health Network and University of Toronto, Toronto, Ontario, Canada.
Department of Medical Imaging, University Health Network and University of Toronto, Toronto, Ontario, Canada.
Sci Rep. 2019 Jul 29;9(1):10996. doi: 10.1038/s41598-019-47206-4.
Total kidney volume (TKV) is a validated prognostic biomarker for risk assessment in autosomal dominant polycystic kidney disease (ADPKD). TKV by manual segmentation (MS) is the "gold standard" but is time-consuming and requires expertise. The purpose of this study was to compare TKV-based prognostic performance by ellipsoid (EL) vs. MS in a large cohort of patients. Cross-sectional study of 308 patients seen at a tertiary referral center; all had a standardized MRI with typical imaging of ADPKD. An experienced radiologist blinded to patient clinical results performed all TKV measurements by EL and MS. We assessed the agreement of TKV measurements by intraclass correlation(ICC) and Bland-Altman plot and also how the disagreement of the two methods impact the prognostic performance of the Mayo Clinic Imaging Classification (MCIC). We found a high ICC of TKV measurements (0.991, p < 0.001) between EL vs. MS; however, 5.5% of the cases displayed disagreement of TKV measurements >20%. We also found a high degree of agreement of the individual MCIC risk classes (i.e. 1A to 1E) with a Cohen's weighted-kappa of 0.89; but 42 cases (13.6%) were misclassified by EL with no misclassification spanning more than one risk class. The sensitivity and specificity of EL in distinguishing low-risk (1A-B) from high-risk (1C-E) MCIC prognostic grouping were 96.6% and 96.1%, respectively. Overall, we found an excellent agreement of TKV-based risk assessment between EL and MS. However, caution is warranted for patients with MCIC 1B and 1C, as misclassification can have therapeutic consequence.
肾脏总体积（TKV）是一种经过验证的用于评估常染色体显性多囊肾病（ADPKD）风险的预后生物标志物。手动分割（MS）的 TKV 是“金标准”，但耗时且需要专业知识。本研究的目的是比较基于椭球（EL）和 MS 的 TKV 预后性能在大型患者队列中的表现。对在三级转诊中心就诊的 308 例患者进行的横断面研究；所有患者均进行了标准 MRI 检查，具有 ADPKD 的典型影像学表现。一位经验丰富的放射科医生在不知道患者临床结果的情况下，通过 EL 和 MS 对所有 TKV 进行了测量。我们通过组内相关系数（ICC）和 Bland-Altman 图评估了 TKV 测量的一致性，并评估了两种方法的差异如何影响 Mayo 临床成像分类（MCIC）的预后性能。我们发现 EL 与 MS 之间的 TKV 测量值具有很高的 ICC（0.991，p<0.001）；然而，有 5.5%的病例显示 TKV 测量值差异>20%。我们还发现 MCIC 风险类别（即 1A 至 1E）的个体具有很高的一致性，Cohen 加权kappa 值为 0.89；但是，有 42 例（13.6%）被 EL 错误分类，没有一个风险类别跨越一个以上的风险类别。EL 在区分低风险（1A-B）和高风险（1C-E）MCIC 预后分组方面的敏感性和特异性分别为 96.6%和 96.1%。总体而言，我们发现 EL 和 MS 之间基于 TKV 的风险评估具有极好的一致性。然而，对于 MCIC 1B 和 1C 的患者，需要谨慎，因为错误分类可能会产生治疗后果。
